TOKYO — Ronan Sato, a graduate student in applied statistics at Oxford University in England, has always been keen to work in his native Japan. But at a careers fair for overseas Japanese students, he found that corporate Japan did not reciprocate his enthusiasm.


In meetings with a handful of Japanese financial trading firms at the forum in Boston last November, none would offer him a job without further interviews in Tokyo.


So Mr. Sato, who received three offers on the spot from non-Japanese corporations, accepted a position in Tokyo with a big British bank.


“I really wanted to gain experience at a Japanese company, but they seemed cautious,” Mr. Sato said. “Do Japanese companies really want global talent? It seemed to me like they’re not really serious.”


Notoriously insular, corporate Japan has long been wary of embracing Western-educated compatriots who return to the homeland. But critics say the reluctance to tap the international experience of these young people is a growing problem for Japan as some of its major industries — like banking, consumer electronics and automobiles — lose ground in an increasingly global economy.


Discouraged by their career prospects if they study abroad, even at elite universities, a shrinking portion of Japanese college students is seeking a Western education. At the same time, regional rivals like China, South Korea and India are sending increasing numbers of students overseas — many of whom, upon graduation, are snapped up by companies back home for their skills, contacts and global outlooks.


“Japanese companies here are missing out on the best foreign talent, and it’s all their fault,” said Toshihiko Irisumi, a graduate of the University of Chicago Booth School of Business and former Goldman Sachs banker. He runs Alpha Leaders, a Tokyo-based consulting firm that helps match top young talent with employers based in Japan. “They really need to change their mind-set.”


A United States-born graduate of Brown University who has a dual citizenship in Japan, one of about a dozen foreign-educated Japanese nationals interviewed for this article, said she was told she “laughed too much” in interviews for a technology job in Tokyo.


Others with Western educations recall being treated with suspicion by Japanese recruiters, who referred to them openly as “over spec” — too elite to fit in, too eager to get ahead and too likely to be poached or to switch employers before long.


What is more, Japanese students who study overseas often find that by the time they enter the job hunt back home, they are far behind compatriots who have already contacted as many as 100 companies and received help from extensive alumni networks. And those who spend too long overseas find they are shut out by rigid age preferences for graduates no older than their mid-20s.


In a survey of 1,000 Japanese companies taken last June on their recruitment plans for the March 2012 fiscal year by the Tokyo-based recruitment company Disco, fewer than a quarter said they planned to hire Japanese applicants who had studied abroad. Even among top companies with more than a thousand employees, less than 40 percent said they wanted to hire Japanese with overseas education. That attitude might help explain why, even as the number of Japanese enrolled in college has held steady at around three million in recent years, the number studying abroad has declined from a peak of nearly 83,000 in 2004 to fewer than 60,000 in 2009 — the most recent year for which the figures are available from the Organization for Economic Cooperation and Development.


In some ways, the Japanese snubbing of Western graduates is a testament to the perceived strength of their own universities, seen by many here as more prestigious than even the best American and European schools — despite their mediocre showing in various global college rankings.


At American universities, only 21,290 Japanese students were registered last year, less than half the number a decade ago — even though the overall number of Japanese enrolled in college has remained constant, at around 3 million. American universities last year had 73,350 students from South Korea, even though it has less than half of Japan’s population,


“There is an awareness that Japan’s competitiveness is falling, and we need a more global work force,” said Kazunori Masugo, head of the Senri International School in western Japan and a member of a central government committee on education and training. Lessons at Senri are taught mostly in English and the school sends a handful of students to colleges in the United States and Europe each year.


“But the environment in Japan is such that if you go overseas to study, you have to be prepared to go your own route, find your own way,” he said.